The present invention relates to filing cabinets, desks, storage units and the like and more particularly to a combined lock and interlock mechanism which prevents the opening of more than one drawer at a time.
Lateral and vertical filing cabinets are typically provided with an interlock mechanism. Such a mechanism prevents the opening of more than one drawer at a time. If not included, there is a danger that the cabinet will tip over and cause injury or damage. Examples of prior interlock mechanisms may be found in U.S. Pat. No. 3,969,008 entitled SAFETY LATCH AND DRAWER MOVEMENT SEQUENCING CONTROL ARRANGEMENT FOR FILE CABINETS and issued on July 13, 1976 to Pergler; U.S. Pat. No. 4,355,851 entitled DRAWER INTERLOCK SYSTEM and issued on Oct. 26, 1982 to Slusser; U.S. Pat. No. 4,429,930 entitled INTERLOCK FOR DRAWERS and issued on Feb. 7, 1984 to Blouin; U.S. Pat. No. 4,480,883 entitled ANTI-TIP LOCKING DEVICE and issued on Nov. 6, 1984 to Young; and U.S Pat. No. 4,711,505 entitled LOCKING SYSTEM and issued on Dec. 8, 1987 to Lakso.
Prior interlock systems have taken many different forms. For example, one system used to prevent the simultaneous opening of drawers includes a ribbon or cable which is connected between the drawers and a support on the frame of the cabinet The cable has a predetermined slack which is taken up when a drawer is fully extended. Other drawers cannot be opened until the open drawer is closed. Other systems employ a plurality of vertically stacked latch bars mounted on one side of the cabinet The drawers are each provided with separate cam members. When one drawer is moved, its cam member engages a cam surface on a latch bar to displace the latch bar. The latch bars then prevent or resist movement of additional drawers. Still other arrangements employ a plurality of lock members or elements mounted within a channel positioned on a side of the cabinet for vertical movement A pivotally mounted cam element and a ball or wedge are provided for each drawer of the cabinet. The cam elements are engaged by pins carried by the file drawers. The free vertical space in the channel supporting the lock elements is limited to the space required for the opening of one drawer. Rotation of a cam element shifts the ball and wedge and the lock elements to prevent opening of additional drawers.
A need exists for an interlock system which is readily adaptable to different file cabinet and drawer configurations, which employs standardized components and which may be easily assembled without the use of special tools. A need exists for a system which insures that an actuator is held in a positive manner in its operative position to eliminate unintentional shifting due to jarring and the like. Further, a need exists for an interlock mechanism which can also readily lock all drawers of a cabinet.